The present invention relates generally to a hand tool for finishing tubing materials and, more particularly, to a manually manipulated belt grinder or abrading tool that is operable to finish opposing sides of a tubing member simultaneously.
Manually manipulated miniature belt grinders are used within small cavities or restricted openings in sheet metal, castings, forgings and the like for deburring and finishing operations. The miniature belt grinders are typically constructed with an endless belt having an outer abrasive surface trained about a drive pulley and a contact pulley. The endless belt corresponds to an outwardly extending arm so that the metallic material to be finished can be engaged with either side of the abrasive belt. A pneumatic motor typically provides the operative power for rotating the abrasive belt so that the tool can be driven through manipulation of a hand control while the rotated belt is pressed against the metallic surface to be finished. Conventionally, the pneumatic motors used to drive the belt grinders are suitably fixed to the casing of the grinder such that they provide a convenient grinder manipulating handle with the drive shaft thereof extending into the casing and serving to support and effect driven rotating of the drive pulley about which one end of the abrasive belt is entrained.
One such miniature belt grinding tool can be found in U.S. Pat. No. 4,368,597, issued to Elwin H. Fleckenstein, et al on Jan. 18, 1983, and in U.S. Pat. No. 4,411,106, issued to Elwin H. Fleckenstein on Oct. 25, 1983. The Fleckenstein grinding tool is pneumatically driven and is formed with a single arm on which is mounted a drive pulley and a tensioning idler pulley with the abrasive belt being entrained around the pulleys to be engagable with the metallic surface to effect a finishing thereof. Similar tools are taught in U.S. Pat. No. 4,754,579, issued to Dennis M. Batt on Jul. 5, 1988, in which a dust collection apparatus is associated with the rotating abrasive belt to minimize the dispersal of dust during the operation of the portable hand-held implement. Such grinding devices are also constructed in a configuration that is adapted for attachment to a rotary power tool, as is shown in U.S. Pat. No. 4,858,390, issued to Nisan Kenig on Aug. 22, 1989, and in U.S. Pat. No. 5,031,362, issued to Reinhold Reiling on Jul. 16, 1991. As with the pneumatically power miniature grinding tools, the abrasive belt is entrained around drive and tensioning pulleys mounted on a single outwardly extending arm.
The abrasive belt can also be mounted in a triangular configuration to facilitate utilization thereof against a cylindrical tubing member by entraining the abrasive belt around three pulleys, one drive pulley and a pair of spaced apart idler pulleys between which the tubular object to be finished can be positioned so that the abrasive belt can form around the cylindrical surface of the tubing member for enhanced engagement thereof. As is depicted in U.S. Pat. No. 3,566,549, issued to James A. Britton on Mar. 2, 1971, and in U.S. Pat. No. 5,628,678, issued to Frank Tridico on May 13, 1997, the second idler pulley can be mounted on a second mounting arm that is spring-loaded away from the main housing of the tool. When the abrasive belt is placed into engagement with a tubular member to effect a finishing operation thereon, the second arm yields against the biasing apparatus to permit the abrasive belt to partially wrap around the surface of the tubing member. While up to about half of the cylindrical surface of the tubing member can be finished, the tool would have to be oriented in an opposing direction in order to finish the opposing half of the tubing member.
Accordingly, it would be desirable to provide a hand grinder apparatus that would be operable to finish opposing sides of a tubing member simultaneously so that the finishing operation for a tubing member can be accomplished more quickly than with the belt grinder devices known in the art.